The tradeoff between soil erosion protection and water consumption in revegetation: Evaluation of new indicators and influencing factors

Abstract

Soil conservation and soil water storage are two of the main ecosystem functions affected by revegetation programs. However, the effects of revegetation on these variables have traditionally been studied separately, and there have been few efforts to assess their responses to revegetation in an integrated way. This paper evaluates the tradeoff between these responses by introducing two new indicators: the accumulation of the ratio between soil erosion protection and water consumption over a prescribed time period (EEWA) and the time specific ratio of the reduction in soil water to the reduction in erosion by vegetation (EEW). Micro-plot experiments involving different vegetation types, clipping treatments, and rainfall intensities were conducted, revealing that analyses based on EEWA identified different dominant factors and optimal management strategies than would be obtained by considering either soil conservation or soil water contents in isolation. The vegetation type, clipping, and rainfall intensity all affected soil erosion by changing the level of soil protection and the driving forces of erosion. Vegetation type and clipping affected soil water storage during and after simulated rainfall but the impact of rainfall intensity was limited because even the mildest rainfall treatment exceeded the soil's infiltration capacity. The results confirmed that it is possible to retain the soil conservation benefits of revegetation programs while avoiding detrimental soil water consumption by manipulating factors such as the vegetation type and clipping regime. These findings will provide useful guidance for increasing the sustainability of revegetation programs, particularly in arid areas where soil water is often a limiting factor for vegetation survival.